A variety of factors can dictate how a feedstock is used in a refinery. One consideration can be the hydrogen required to process a feedstock to a desired product. For example, if hydrotreatment of a feed will require more hydrogen than is economically available, the feed may instead be used for a process with lower hydrogen requirements, such as fluid catalytic cracking. As a result, considerations such as hydrogen consumption can limit the flexibility of a refinery to change the products generated from a given input crude oil.
U.S. Pat. Nos. 7,291,257 and 6,123,835 describe systems and methods for processing feedstocks that involve processing the feed in a reactor having a continuous liquid phase. The methods include using a diluent material as a means for supplying hydrogen necessary for a process. Various methods for adding a diluent to the feed are described, such as recycling a portion of the product. Processes performed in a continuous liquid phase reactor include hydrotreatment, hydrocracking, and hydroisomerization.
U.S. Published Patent Application No. 2009/0095653 describes a system and method for performing a hydroisomerization process. The hydroisomerization is performed in a reactor that has a substantially continuous liquid phase. An excess of hydrogen gas can be present beyond the solubility limit of the feedstock. However, the flowing medium in the reactor is described as being substantially liquid-continuous. The excess hydrogen gas is described as allowing the liquid phase to remain saturated with hydrogen as the reaction proceeds.